This is a question we are asked a lot. Many of our customers have two main service panels to cover all of the electrical needs in their home and would like to either back up their whole home or specific breakers from each. For example, you might have the breaker for your air conditioning on one panel and your refrigerator on the other and would like to continue to have power to both during a grid outage.
This is a complicated issue and depends on your specific arrangement and power needs, but the basic answer here is that you can’t normally split the power from your Powerwalls onto both panels.
The Gateway: The Brains of the Powerwall
The reason you can’t split your backup power between two main panels is that it is a code and safety issue. A Powerwall needs to be installed with a Gateway, which is like the brains of the Powerwall. It’s a separate box that controls connection to the grid, automatically detecting outages and providing a seamless transition to backup power. The Gateway is rated to back up 200 amps, and one service panel is limited to 200 amps, hence the inability to back up two service panels with one Gateway. Doing so would be against code and would also be a fire hazard.
Solutions Specific to Your Home and Energy Needs
Solution One: There are several solutions that our master electricians and engineers can design when there are two main service panels. The first option is to decide on just one panel to back up. The only exception to this is if your panels each have a service of 100 amps for a total of 200 between them, but typically each panel is 200 amps for a total of 400 amps.
Depending on your specific situation, your personal electrician may be able to move some of the breakers from one panel to another so that you can choose which breakers you want backed up. We recommend that you have this done while your Powerwall project is in the permitting phase, so that there’s plenty of time to have the work done in advance. Depending on how many breakers you want moved, you should be able to have this done for around $1500.
This is what it looks like when just one service panel is backed up by one Gateway:
Solution Two: Another solution we can design for customers is to install two Gateways so that they can fully back up both panels. This is obviously the most costly, but also the most foolproof situation since it enables you to truly back up your entire house and all of the electrical systems and appliances you may need.
This is an example of two Gateways, each backing up one panel:
Adding a Whole Home Disconnect
It’s important to note that if your Gateway is located outside of your home and your panels are inside either for space or aesthetic reasons, we will need to add a Whole Home Disconnect outside, as shown below. This is to comply with fire code, for the safety of your home and any personnel who may be called to work on your electrical system.
Give Us a Call to Learn More!
The bottom line is that we are dedicated to bringing you the best, and safest, solution for your home. Our solar experts will listen to you and work with you to design a system that’s tailored to your needs. Give us a call today at 703-249-6594 or click below to talk about the possibilities!